/**
 * JDBM LICENSE v1.00
 *
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. The name "JDBM" must not be used to endorse or promote products derived
 * from this Software without prior written permission of Cees de Groot. For
 * written permission, please contact cg@cdegroot.com.
 *
 * 4. Products derived from this Software may not be called "JDBM" nor may
 * "JDBM" appear in their names without prior written permission of Cees de
 * Groot.
 *
 * 5. Due credit should be given to the JDBM Project
 * (http://jdbm.sourceforge.net/).
 *
 * THIS SOFTWARE IS PROVIDED BY THE JDBM PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 2001 (C) Alex Boisvert. All Rights Reserved. Contributions are
 * Copyright (C) 2001 by their associated contributors.
 *
 */
package sg.atom.utils._commons;

/**
 * Miscelaneous conversion utility methods. Replace with Common Lang or IO.
 *
 * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
 * @version $Id: Conversion.java,v 1.3 2002/05/31 06:33:20 boisvert Exp $
 */
public class Conversion {

    /**
     * Convert a string into a byte array.
     */
    public static byte[] convertToByteArray(String s) {
        try {
            // see the following page for character encoding
            // http://java.sun.com/products/jdk/1.1/docs/guide/intl/encoding.doc.html
            return s.getBytes("UTF8");
        } catch (java.io.UnsupportedEncodingException uee) {
            uee.printStackTrace();
            throw new Error("Platform doesn't support UTF8 encoding");
        }
    }

    /**
     * Convert a byte into a byte array.
     */
    public static byte[] convertToByteArray(byte n) {
        n = (byte) (n ^ ((byte) 0x80)); // flip MSB because "byte" is signed
        return new byte[]{n};
    }

    /**
     * Convert a short into a byte array.
     */
    public static byte[] convertToByteArray(short n) {
        n = (short) (n ^ ((short) 0x8000)); // flip MSB because "short" is signed
        byte[] key = new byte[2];
        pack2(key, 0, n);
        return key;
    }

    /**
     * Convert an int into a byte array.
     */
    public static byte[] convertToByteArray(int n) {
        n = (n ^ 0x80000000); // flip MSB because "int" is signed
        byte[] key = new byte[4];
        pack4(key, 0, n);
        return key;
    }

    /**
     * Convert a long into a byte array.
     */
    public static byte[] convertToByteArray(long n) {
        n = (n ^ 0x8000000000000000L); // flip MSB because "long" is signed
        byte[] key = new byte[8];
        pack8(key, 0, n);
        return key;
    }

    /**
     * Convert a byte array (encoded as UTF-8) into a String
     */
    public static String convertToString(byte[] buf) {
        try {
            // see the following page for character encoding
            // http://java.sun.com/products/jdk/1.1/docs/guide/intl/encoding.doc.html
            return new String(buf, "UTF8");
        } catch (java.io.UnsupportedEncodingException uee) {
            uee.printStackTrace();
            throw new Error("Platform doesn't support UTF8 encoding");
        }
    }

    /**
     * Convert a byte array into an integer (signed 32-bit) value.
     */
    public static int convertToInt(byte[] buf) {
        int value = unpack4(buf, 0);
        value = (value ^ 0x80000000); // flip MSB because "int" is signed
        return value;
    }

    /**
     * Convert a byte array into a long (signed 64-bit) value.
     */
    public static long convertToLong(byte[] buf) {
        long value = ((long) unpack4(buf, 0) << 32)
                + (unpack4(buf, 4) & 0xFFFFFFFFL);
        value = (value ^ 0x8000000000000000L); // flip MSB because "long" is signed
        return value;
    }

    static int unpack4(byte[] buf, int offset) {
        int value = (buf[ offset] << 24)
                | ((buf[ offset + 1] << 16) & 0x00FF0000)
                | ((buf[ offset + 2] << 8) & 0x0000FF00)
                | ((buf[ offset + 3] << 0) & 0x000000FF);

        return value;
    }

    static final void pack2(byte[] data, int offs, int val) {
        data[offs++] = (byte) (val >> 8);
        data[offs++] = (byte) val;
    }

    static final void pack4(byte[] data, int offs, int val) {
        data[offs++] = (byte) (val >> 24);
        data[offs++] = (byte) (val >> 16);
        data[offs++] = (byte) (val >> 8);
        data[offs++] = (byte) val;
    }

    static final void pack8(byte[] data, int offs, long val) {
        pack4(data, 0, (int) (val >> 32));
        pack4(data, 4, (int) val);
    }
}
